CN115700935A - Positive current collector solid electrolyte coating, positive pole piece, preparation method and application - Google Patents
Positive current collector solid electrolyte coating, positive pole piece, preparation method and application Download PDFInfo
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Abstract
The invention discloses a positive current collector solid electrolyte coating, a positive pole piece, a preparation method and application thereof, wherein the positive current collector solid electrolyte coating comprises the following components: a first conductive agent, an inorganic solid electrolyte, and a first binder; the first conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber; the inorganic solid electrolyte includes: beta-Al 2 O 3 、Na 1+x Zr 2 Si x P 3‑x O 12 、Na 3 PS 4 、Na 3 PSe 4 、Na 3 SbS 4 、Na 10 SnP 2 S 12 、Na 2 S‑P 2 S 5 、Na 2 B 12 H 12 Wherein x is more than or equal to 0 and less than or equal to 3; inorganic solid state electrolysisThe particle size Dv50 of the substance is between 100nm and 1.5 μm; the first binder includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI); the solid electrolyte coating of the positive current collector can be used for preparing a positive pole piece of a sodium battery and used in the sodium battery, and can improve the safety performance of the sodium battery.
Description
Technical Field
The invention relates to the technical field of sodium battery materials, in particular to a positive current collector solid electrolyte coating, a positive pole piece, a preparation method and application.
Background
In recent decades, lithium ion batteries have become more and more popular for use in the fields of electric vehicles, consumer electronics and energy storage. However, lithium resources are scarce, and the application of the lithium ion battery is limited by the high cost brought by the scarcity of the lithium resources. The sodium ion battery has unique competitive advantages in cost compared with the lithium ion battery due to abundant sodium reserves, and can be used in low-end markets.
However, sodium ion batteries also present safety hazards during application, particularly in overcharge, overdischarge, external force extrusion and impact, and high temperature environments. Under bad working conditions, the battery is easy to have internal short circuit, the temperature rise caused by heat accumulation in a short time can induce many exothermic side reactions in the battery, a chain effect is generated, and finally the battery evolves into thermal runaway.
In order to solve the above problems, a common strategy is to coat and dope the positive electrode material of the sodium-ion battery, so as to improve the thermal stability. However, the energy density or rate performance of the sodium ion battery is often sacrificed by the strategy, and the problem of potential safety hazard caused by side reaction heat release between the cathode active material with weak chemical stability and the aluminum foil cannot be solved. In order to overcome the technical problem, it is necessary to modify the positive electrode current collector of the sodium ion battery appropriately. The solid electrolyte has good chemical stability, electrochemical stability and thermal stability, can inhibit the initial reaction step of the exothermic chain reaction in the thermal runaway process of the sodium battery, and improves the safety performance of the battery. The solid electrolyte coating is coated on the surface of the positive current collector of the sodium battery, so that the safety performance of the battery is ensured, the positive current collector has ionic conductivity and electronic conductivity, and the dynamic performance of a positive material is favorably exerted.
Disclosure of Invention
The embodiment of the invention provides a solid electrolyte coating of a positive current collector, a positive pole piece, a preparation method and application, and aims to solve the safety problem of the existing sodium battery.
In a first aspect, embodiments of the present invention provide a positive current collector solid-state electrolyte coating, including: a first conductive agent, an inorganic solid electrolyte, and a first binder;
the first conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber;
the inorganic solid electrolyte includes: beta-Al 2 O 3 、Na 1+x Zr 2 Si x P 3-x O 12 、Na 3 PS 4 、Na 3 PSe 4 、Na 3 SbS 4 、Na 10 SnP 2 S 12 、Na 2 S-P 2 S 5 、Na 2 B 12 H 12 Wherein x is more than or equal to 0 and less than or equal to 3;
the particle size Dv50 of the inorganic solid electrolyte is between 100nm and 1.5 mu m;
the first adhesive includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI);
the mass of the first conductive agent accounts for 5% -20% of the total mass of the positive current collector solid electrolyte coating;
the inorganic solid electrolyte accounts for 60-80% of the total mass of the positive current collector solid electrolyte coating;
the first binder accounts for 5-30% of the total mass of the positive current collector solid electrolyte coating;
the positive current collector solid electrolyte coating is used for preparing a positive pole piece of a sodium battery.
In a second aspect, an embodiment of the present invention provides a positive electrode tab, where the positive electrode tab includes the positive current collector solid electrolyte coating described in the first aspect;
the positive pole piece also comprises a positive current collector and a positive active material coating.
Preferably, the positive current collector solid electrolyte coating is coated on the two side surfaces of the positive current collector; the positive current collector is aluminum foil;
the positive current collector solid electrolyte coating is a single layer and has a thickness of 0.2-10 μm;
the positive active material coating is coated on the surface of the positive current collector solid electrolyte coating; the thickness of the positive active material coating is 20-110 μm.
Preferably, the positive active material coating layer includes: a positive electrode active material, a second conductive agent, and a second binder;
the mass of the second conductive agent accounts for 0-10% of the total mass of the positive electrode active material coating;
the positive electrode active material accounts for 90-99% of the total mass of the positive electrode active material coating;
the second binder accounts for 1-10% of the total mass of the positive electrode active material coating.
Further preferably, the positive electrode active material includes: naCoO 2 、NaFePO 4 、NaMnO 2 、Na x TiS 2 、Na x NbS 2 C 12 、Na x WO 3-y 、Na x V 0.5 Cr 0.5 S、Na x MoS 3 、Na x TaS 2 Wherein 0 < x < 2,0 < y < 1;
the second conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber;
the second binder includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI).
In a third aspect, an embodiment of the present invention provides a method for preparing a positive electrode plate in the second aspect, where the method includes:
step S1, uniformly mixing inorganic solid electrolyte, a first conductive agent, a first binder and a first solvent to prepare solid electrolyte coating slurry of a positive current collector;
s2, coating the slurry of the solid electrolyte coating of the positive current collector on two sides of the positive current collector through a roller coating, spraying or micro-gravure coating process, placing the positive current collector in a vacuum drying oven, and drying the positive current collector in vacuum at 100-160 ℃ to obtain the positive current collector containing the solid electrolyte coating of the positive current collector;
s3, uniformly mixing the positive active material, a second conductive agent, a second binder and a second solvent to prepare positive active material coating slurry;
and S4, coating the positive active material coating slurry on the surface of the positive current collector solid electrolyte coating by a roller coating or spraying process method, placing the positive current collector solid electrolyte coating in a vacuum drying oven, and drying the positive current collector solid electrolyte coating in vacuum at 100-160 ℃ to obtain the positive pole piece containing the positive current collector solid electrolyte coating and the positive active material coating.
Preferably, the first conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber;
the inorganic solid electrolyte includes: beta-Al 2 O 3 、Na 1+x Zr 2 Si x P 3-x O 12 、Na 3 PS 4 、Na 3 PSe 4 、Na 3 SbS 4 、Na 10 SnP 2 S 12 、Na 2 S-P 2 S 5 、Na 2 B 12 H 12 Wherein x is more than or equal to 0 and less than or equal to 3;
the particle size Dv50 of the inorganic solid electrolyte is between 100nm and 1.5 mu m;
the first binder includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI);
the first solvent includes: one or more of water, ethanol, acetone and isopropanol; the solid content of the solid electrolyte coating slurry of the positive current collector is 10-50%;
the positive electrode active material includes: naCoO 2 、NaFePO 4 、NaMnO 2 、Na x TiS 2 、Na x NbS 2 C 12 、Na x WO 3-y 、Na x V 0.5 Cr 0.5 S、Na x MoS 3 、Na x TaS 2 Wherein 0 < x < 2,0 < y < 1;
the second conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber;
the second binder includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI);
the second solvent includes: one or more of water, ethanol, acetone and isopropanol; the solid content of the positive electrode active material coating slurry is 50-80%.
In a fourth aspect, an embodiment of the present invention provides a sodium battery, where the sodium battery includes the positive electrode tab of the second aspect.
Preferably, the sodium battery comprises: any one of a liquid sodium ion battery, a sodium sulfur battery, a sodium air battery, a solid-liquid mixed sodium battery, or an all-solid-state sodium battery.
The positive current collector solid electrolyte coating prepared by the inorganic solid electrolyte can effectively prevent a positive active material from being in direct contact with a positive current collector of a sodium battery, can improve the overcharge resistance of the sodium battery, inhibits the initial reaction step of an exothermic chain reaction in the thermal runaway process of the sodium battery, improves the safety performance of the battery, and simultaneously can enable the positive current collector to have ionic conductance and electronic conductance, is favorable for exerting the dynamic performance of the positive active material and provides the multiplying power performance of the sodium battery.
The preparation method of the positive pole piece containing the positive current collector solid electrolyte coating provided by the embodiment of the invention is simple to operate and is suitable for large-scale industrial production.
Drawings
The technical solutions of the embodiments of the present invention are further described in detail with reference to the accompanying drawings and embodiments.
Fig. 1 is a flowchart of a method for manufacturing a positive electrode sheet according to an embodiment of the present invention.
Fig. 2 is a schematic cross-sectional structure diagram of a positive electrode tab according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples, but it should be understood that these examples are for the purpose of illustration only and are not to be construed as limiting the invention in any way, i.e., not as limiting the scope of the invention.
The embodiment of the invention provides a positive current collector solid electrolyte coating, which comprises the following components in part by weight: a first conductive agent, an inorganic solid electrolyte, and a first binder.
Wherein the first conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber; the mass percentage of the first conductive agent in the total mass of the solid electrolyte coating of the positive electrode current collector is 5-20%.
The inorganic solid electrolyte includes: beta-Al 2 O 3 、Na 1+x Zr 2 Si x P 3-x O 12 、Na 3 PS 4 、Na 3 PSe 4 、Na 3 SbS 4 、Na 10 SnP 2 S 12 、Na 2 S-P 2 S 5 、Na 2 B 12 H 12 Wherein x is more than or equal to 0 and less than or equal to 3; the particle size Dv50 of the inorganic solid electrolyte is between 100nm and 1.5 mu m; the inorganic solid electrolyte accounts for 60-80% of the total mass of the positive current collector solid electrolyte coating;
the first binder includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI); the percentage of the first binder in the total mass of the positive electrode current collector solid electrolyte coating is 5-30%.
The embodiment of the invention provides a positive pole piece which comprises the positive current collector solid electrolyte coating, a positive current collector aluminum foil and a positive active material coating.
The solid electrolyte coating of the positive current collector is coated on the two side surfaces of the positive current collector; the solid electrolyte coating of the positive current collector is a single layer, and the thickness of the solid electrolyte coating is 0.2-10 mu m; the positive active material coating is coated on the surface of the positive current collector solid electrolyte coating; the thickness of the coating layer of the positive electrode active material is 20 μm to 110 μm.
The positive active material coating layer includes: a positive electrode active material, a second conductive agent, and a second binder;
the second conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber; the mass of the second conductive agent accounts for 0-10% of the total mass of the positive active material coating;
the positive electrode active material includes: naCoO 2 、NaFePO 4 、NaMnO 2 、Na x TiS 2 、Na x NbS 2 C 12 、Na x WO 3-y 、Na x V 0.5 Cr 0.5 S、Na x MoS 3 、Na x TaS 2 Wherein 0 < x < 2,0 < y < 1; the positive active material accounts for 90-99% of the total mass of the solid positive active material coating;
the second binder includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI); the second binder accounts for 1-10% of the total mass of the positive active material coating.
The embodiment of the invention provides a preparation method of the positive pole piece, which comprises the following steps of:
step S1, uniformly mixing inorganic solid electrolyte, a first conductive agent, a first binder and a first solvent to prepare solid electrolyte coating slurry of a positive current collector;
wherein the first conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber;
the inorganic solid electrolyte includes: beta-Al 2 O 3 、Na 1+x Zr 2 Si x P 3-x O 12 、Na 3 PS 4 、Na 3 PSe 4 、Na 3 SbS 4 、Na 10 SnP 2 S 12 、Na 2 S-P 2 S 5 、Na 2 B 12 H 12 Wherein x is more than or equal to 0 and less than or equal to 3;
the particle size Dv50 of the inorganic solid electrolyte is between 100nm and 1.5 mu m;
the first binder includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI);
the first solvent includes: one or more of water, ethanol, acetone and isopropanol; the solid content of the solid electrolyte coating slurry of the positive electrode current collector is 10-50%.
S2, coating the slurry of the solid electrolyte coating of the positive current collector on two sides of the positive current collector through roller coating, spraying or micro-gravure coating processes, placing the positive current collector in a vacuum drying oven, and drying the positive current collector in vacuum at 100-160 ℃ to obtain the positive current collector containing the solid electrolyte coating of the positive current collector;
wherein, the positive current collector is aluminum foil.
S3, uniformly mixing the positive active material, a second conductive agent, a second binder and a second solvent to prepare positive active material coating slurry;
wherein the positive electrode active material includes: naCoO 2 、NaFePO 4 、NaMnO 2 、Na x TiS 2 、Na x NbS 2 C 12 、Na x WO 3-y 、Na x V 0.5 Cr 0.5 S、Na x MoS 3 、Na x TaS 2 Wherein 0 < x < 2,0 < y < 1;
the second conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber;
the second adhesive includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI);
the second solvent includes: one or more of water, ethanol, acetone and isopropanol; the solid content of the coating slurry of the positive electrode active material is 50-80%.
And S4, coating the positive active material coating slurry on the surface of the positive current collector solid electrolyte coating by a roller coating or spraying process method, placing the positive current collector solid electrolyte coating in a vacuum drying oven, and drying the positive current collector solid electrolyte coating in vacuum at 100-160 ℃ to obtain the positive pole piece containing the positive current collector solid electrolyte coating and the positive active material coating.
As shown in fig. 2, the sectional structure of the positive electrode plate prepared in the embodiment of the present invention is schematically illustrated, wherein the positive current collector solid electrolyte coating is coated on the two side surfaces of the positive current collector aluminum foil, and the positive active material coating is coated on the surface of the positive current collector solid electrolyte coating.
The positive pole piece prepared by the embodiment of the invention can be applied to a sodium battery, and the sodium battery comprises: any one of a liquid sodium ion battery, a sodium-sulfur battery, a sodium-air battery, a solid-liquid mixed sodium battery, or an all-solid-state sodium battery; the anode current collector solid electrolyte coating based on anode protection has controllable thickness and conductivity, high electronic conductivity, high ionic conductivity, high bonding force and high mechanical strength, and is favorable for improving the comprehensive performance of the sodium battery.
In order to better understand the technical solutions provided by the present invention, the following specific examples respectively illustrate the preparation method and characteristics of the positive current collector solid electrolyte coating of the present invention.
Example 1
The embodiment provides a preparation process and a performance test of a positive pole piece containing a positive current collector solid electrolyte coating, and the specific steps are as follows.
(1) According to the mass ratio of 60:20:20 weighing inorganic solid electrolyte beta-Al 2 O 3 And uniformly mixing the first conductive agent carbon black and the first binder CMC with deionized water to prepare the solid electrolyte coating slurry of the positive current collector, wherein the solid content in the slurry accounts for 50%.
(2) Coating the slurry of the solid electrolyte coating of the positive current collector on two sides of the positive current collector by a roller coating process, placing the slurry in a vacuum drying oven, baking the slurry for 2 hours at 100 ℃ in vacuum, and drying to obtain the positive current collector containing the solid electrolyte coating of the positive current collector, wherein the single-layer thickness of the solid electrolyte coating of the positive current collector is 2 mu m;
(3) According to the mass ratio of 60:20:2 weighing the anode active material NaCoO 2 Uniformly mixing a second conductive agent carbon black, a second binder PVDF and NMP to prepare the coating slurry of the positive active material, wherein the solid content in the slurry accounts for 80%;
(4) Coating the positive electrode active material coating slurry on the surface of a positive electrode current collector solid electrolyte coating by a roller coating process method, placing the positive electrode current collector solid electrolyte coating in a vacuum drying oven, baking the positive electrode current collector solid electrolyte coating for 1 hour at 160 ℃, and drying to obtain the positive electrode piece containing the positive electrode current collector solid electrolyte coating and the positive electrode active material coating, wherein the single-layer thickness of the positive electrode active material coating is 80 mu m.
The ionic conductivity and sheet resistance of the positive electrode sheet prepared in this example were measured, and the test results are shown in table 1.
The ionic conductivity is obtained by testing an electrochemical workstation (ZENNIUM, ZAHNER), and the square resistance value of the pole piece is obtained by testing a pole piece resistance meter (IEST Meta energy technology, model BER 2500).
The prepared positive pole piece and the hard carbon negative pole piece of the sodium battery are assembled into a button battery by a conventional method and used for testing the overcharge resistance and the rate capability of the battery.
The test method comprises the steps of charging at constant current with the multiplying power of 0.5C at room temperature until the charging termination voltage is reached, then converting to constant voltage charging until the multiplying power of the charging current is reduced to 0.01C, stopping charging, standing for 0.5h, and then recording the overcharge voltage of the battery. Charging to the charge termination voltage at 0.1C,0.2C,0.5C,1C and 3C multiplying factors respectively, standing for 1min, converting to the same multiplying factor current, discharging to the discharge termination voltage, and standing for 1min. And (4) after 5 times of circulation of the same multiplying power, calculating the average discharge capacity at each multiplying power. The test results are shown in Table 2
Example 2
The embodiment provides a preparation process and a performance test of a positive pole piece containing a positive current collector solid electrolyte coating, and the specific steps are as follows.
(1) According to the mass ratio of 60:20:20 weighing inorganic solid electrolyte beta-Al 2 O 3 And uniformly mixing the first conductive agent carbon black and the first binder CMC with deionized water to prepare the solid electrolyte coating slurry of the positive current collector, wherein the solid content in the slurry accounts for 50%.
(2) Coating the slurry of the solid electrolyte coating of the positive current collector on two sides of the positive current collector by a roller coating process, placing the positive current collector in a vacuum drying oven, baking the positive current collector for 2 hours at 100 ℃ in vacuum, and drying to obtain the positive current collector containing the solid electrolyte coating of the positive current collector, wherein the single-layer thickness of the solid electrolyte coating of the positive current collector is 10 mu m;
(3) According to the mass ratio of 60:20:2 weighing the anode active material NaCoO 2 Uniformly mixing a second conductive agent carbon black, a second binder PVDF and NMP to prepare the coating slurry of the positive active material, wherein the solid content in the slurry accounts for 80%;
(4) Coating the positive active material coating slurry on the surface of a positive current collector solid electrolyte coating by a roller coating process method, placing the positive current collector solid electrolyte coating in a vacuum drying oven, baking the positive current collector solid electrolyte coating for 1 hour at 160 ℃, and drying to obtain the positive pole piece containing the positive current collector solid electrolyte coating and the positive active material coating, wherein the single-layer thickness of the positive active material coating is 20 microns.
The positive electrode sheet prepared in this example was tested for ionic conductivity and sheet resistance in the same manner as in example 1, and the test results are shown in table 1.
The positive electrode plate prepared in this example was assembled into a lithium battery and tested, the assembly process and the test method were the same as those of example 1, and the test results are shown in table 2.
Example 3
The embodiment provides a preparation process and a performance test of a positive pole piece containing a positive current collector solid electrolyte coating, and the specific steps are as follows.
(1) According to the mass ratio of 60:20:20 weighing inorganic solid electrolyte beta-Al 2 O 3 And uniformly mixing the first conductive agent carbon black and the first binder CMC with deionized water to prepare the solid electrolyte coating slurry of the positive current collector, wherein the solid content in the slurry accounts for 50%.
(2) Coating the slurry of the solid electrolyte coating of the positive current collector on two sides of the positive current collector by a roller coating process, placing the slurry in a vacuum drying oven, baking the slurry for 2 hours at 100 ℃ in vacuum, and drying to obtain the positive current collector containing the solid electrolyte coating of the positive current collector, wherein the single-layer thickness of the solid electrolyte coating of the positive current collector is 0.2 mu m;
(3) According to the mass ratio of 60:20:2 weighing the anode active material NaCoO 2 Uniformly mixing a second conductive agent carbon black, a second binder PVDF and NMP to prepare the coating slurry of the positive active material, wherein the solid content in the slurry accounts for 80%;
(4) Coating the positive active material coating slurry on the surface of a positive current collector solid electrolyte coating by a roller coating process method, placing the positive current collector solid electrolyte coating in a vacuum drying oven, baking the positive current collector solid electrolyte coating for 1 hour at 160 ℃, and drying to obtain the positive pole piece containing the positive current collector solid electrolyte coating and the positive active material coating, wherein the single-layer thickness of the positive active material coating is 110 mu m.
The positive electrode sheet prepared in this example was tested for ionic conductivity and sheet resistance in the same manner as in example 1, and the test results are shown in table 1.
The positive electrode plate prepared in this example was assembled into a lithium battery and tested, the assembly process and the test method were the same as those of example 1, and the test results are shown in table 2.
To better illustrate the effects of the examples of the present invention, comparative example 1 was compared with the above examples.
Comparative example 1
Comparative example the procedure for preparing a positive electrode sheet was the same as in example 1, but the difference from example 1 was that a positive electrode sheet was used which was not coated with a positive current collector solid-state electrolyte coating, and the positive electrode active material coating of the positive electrode sheet was completely the same as in example 1.
The positive electrode sheet prepared in the comparative example was tested for ionic conductivity and sheet resistance in the same manner as in example 1, and the test results are shown in table 1.
The positive pole piece prepared in the comparative example was assembled into a lithium battery and tested, the assembly process and the test method were the same as in example 1, and the test results are shown in table 2.
Table 1 is a summary of the coating thickness for examples 1-3 and comparative example 1 and the sheet resistance and ionic conductivity test data for the current collectors after the coatings were applied.
TABLE 1
As can be seen from comparison of test data in table 1, the ionic conductivity of the positive electrode pieces containing the composite inorganic solid electrolyte coatings in embodiments 1 to 3 of the present invention is much greater than that of comparative example 1, which indicates that the positive electrode pieces containing the composite inorganic solid electrolyte coatings provided in the embodiments of the present invention have good sodium ion conductivity, and are favorable for the performance of the dynamic performance of the positive active material of the sodium battery. In addition, the sheet resistance values of the positive pole pieces containing the composite inorganic solid electrolyte coatings in the embodiments 1 to 3 of the invention are slightly smaller than that of the comparative example 1, which shows that the positive pole pieces are favorable for reducing the internal polarization of the battery, thereby improving the overall electrochemical performance of the battery.
Table 2 is a summary of the test data for the overcharge voltages and discharge capacities of examples 1-3 and comparative example 1.
| Number of | Overcharge voltage (V) | Multiplying power at room temperature (3C/1C average discharge capacity) |
| Example 1 | 18.9 | 90.2％ |
| Example 2 | 12.5 | 92.1％ |
| Example 3 | 25.3 | 87.4％ |
| Comparative example 1 | 5.4 | 74.8％ |
TABLE 2
By comparing the test data in table 2, it can be seen that the overcharge voltage of the battery assembled by the positive electrode plate containing the composite inorganic solid electrolyte coating in examples 1 to 3 of the present invention is significantly higher than that in comparative example 1, and the ratio of the average discharge capacity at 3C rate to that at 1C rate is significantly higher than that in comparative example, which indicates that the battery assembled by the positive electrode plate of the present invention has higher overcharge resistance and better rate performance at room temperature.
According to the invention, the anode current collector solid electrolyte coating based on anode protection has controllable thickness and conductivity, and has high electronic conductivity, high ionic conductivity, high bonding force and high mechanical strength, thereby being beneficial to improving the comprehensive performance of the sodium battery.
Compared with the prior art, the solid electrolyte coating based on the anode protection provided by the invention can effectively prevent the direct physical contact between the anode active material and the aluminum foil current collector, prevent the occurrence of the exothermic chain reaction of the battery when the sodium battery is in safety failure, and has great practical significance for improving the safety of the sodium battery.
The preparation method of the positive pole piece containing the positive current collector solid electrolyte coating provided by the embodiment of the invention is simple to operate and is suitable for large-scale industrial production.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (9)
1. A positive current collector solid electrolyte coating, comprising: a first conductive agent, an inorganic solid electrolyte, and a first binder;
the first conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber;
the inorganic solid electrolyte includes: beta-Al 2 O 3 、Na 1+x Zr 2 Si x P 3-x O 12 、Na 3 PS 4 、Na 3 PSe 4 、Na 3 SbS 4 、Na 10 SnP 2 S 12 、Na 2 S-P 2 S 5 、Na 2 B 12 H 12 Wherein x is more than or equal to 0 and less than or equal to 3;
the particle size Dv50 of the inorganic solid electrolyte is between 100nm and 1.5 mu m;
the first binder includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI);
the mass of the first conductive agent accounts for 5-20% of the total mass of the positive current collector solid electrolyte coating;
the inorganic solid electrolyte accounts for 60-80% of the total mass of the positive current collector solid electrolyte coating;
the first binder accounts for 5% -30% of the total mass of the positive current collector solid electrolyte coating;
the positive current collector solid electrolyte coating is used for preparing a positive pole piece of a sodium battery.
2. A positive electrode plate, characterized in that the positive electrode plate comprises the positive electrode current collector solid electrolyte coating of claim 1;
the positive pole piece also comprises a positive current collector and a positive active material coating.
3. The positive pole piece of claim 2, wherein the positive current collector solid electrolyte coating is coated on both side surfaces of the positive current collector; the positive current collector is an aluminum foil;
the solid electrolyte coating of the positive current collector is a single layer, and the thickness of the solid electrolyte coating is 0.2-10 mu m;
the positive active material coating is coated on the surface of the positive current collector solid electrolyte coating; the thickness of the positive active material coating is 20-110 μm.
4. The positive electrode sheet according to claim 2, wherein the positive electrode active material coating layer comprises: a positive electrode active material, a second conductive agent, and a second binder;
the mass of the second conductive agent accounts for 0-10% of the total mass of the positive electrode active material coating;
the positive electrode active material accounts for 90-99% of the total mass of the positive electrode active material coating;
the second binder accounts for 1-10% of the total mass of the positive electrode active material coating.
5. The positive electrode sheet according to claim 4, wherein the positive electrode active material comprises: naCoO 2 、NaFePO 4 、NaMnO 2 、Na x TiS 2 、Na x NbS 2 C 12 、Na x WO 3-y 、Na x V 0.5 Cr 0.5 S、Na x MoS 3 、Na x TaS 2 Wherein 0 < x < 2,0 < y < 1;
the second conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber;
the second binder includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI).
6. A preparation method of the positive pole piece of any one of the claims 2 to 5, characterized in that the preparation method comprises the following steps:
step S1, uniformly mixing inorganic solid electrolyte, a first conductive agent, a first binder and a first solvent to prepare solid electrolyte coating slurry of a positive current collector;
s2, coating the slurry of the solid electrolyte coating of the positive current collector on two sides of the positive current collector through a roller coating, spraying or micro-gravure coating process, placing the positive current collector in a vacuum drying oven, and drying the positive current collector in vacuum at 100-160 ℃ to obtain the positive current collector containing the solid electrolyte coating of the positive current collector;
s3, uniformly mixing the positive active material, a second conductive agent, a second binder and a second solvent to prepare positive active material coating slurry;
and S4, coating the positive active material coating slurry on the surface of the positive current collector solid electrolyte coating by a roller coating or spraying process method, placing the positive current collector solid electrolyte coating in a vacuum drying oven, and drying the positive current collector solid electrolyte coating in vacuum at 100-160 ℃ to obtain the positive pole piece containing the positive current collector solid electrolyte coating and the positive active material coating.
7. The production method according to claim 6, wherein the first conductive agent comprises: one or more of carbon black, conductive graphite, vapor grown carbon fiber;
the inorganic solid electrolyte includes: beta-Al 2 O 3 、Na 1+x Zr 2 Si x P 3-x O 12 、Na 3 PS 4 、Na 3 PSe 4 、Na 3 SbS 4 、Na 10 SnP 2 S 12 、Na 2 S-P 2 S 5 、Na 2 B 12 H 12 Wherein x is more than or equal to 0 and less than or equal to 3;
the particle size Dv50 of the inorganic solid electrolyte is between 100nm and 1.5 μm;
the first adhesive includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI);
the first solvent includes: one or more of water, ethanol, acetone and isopropanol; the solid content of the solid electrolyte coating slurry of the positive current collector is 10-50%;
the positive electrode active material includes: naCoO 2 、NaFePO 4 、NaMnO 2 、Na x TiS 2 、Na x NbS 2 C 12 、Na x WO 3-y 、Na x V 0.5 Cr 0.5 S、Na x MoS 3 、Na x TaS 2 Wherein 0 < x < 2,0 < y < 1;
the second conductive agent includes: one or more of carbon black, conductive graphite, vapor grown carbon fiber;
the second binder includes: one or more of sodium carboxymethylcellulose (CMC), styrene Butadiene Rubber (SBR), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and Polyimide (PI);
the second solvent includes: one or more of water, ethanol, acetone and isopropanol; the solid content of the positive electrode active material coating slurry is 50-80%.
8. A sodium battery, characterized in that, the sodium battery comprises the positive pole piece of any one of the claims 2-5.
9. The sodium battery of claim 8, wherein the sodium battery comprises: any one of a liquid sodium ion battery, a sodium sulfur battery, a sodium air battery, a solid-liquid mixed sodium battery, or an all-solid-state sodium battery.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117080448A (en) * | 2023-09-27 | 2023-11-17 | 荣耀终端有限公司 | Semi-solid lithium battery and terminal comprising same |
| CN118156480A (en) * | 2024-05-09 | 2024-06-07 | 浙江华宇钠电新能源科技有限公司 | Method for modifying surface of sodium ion battery oxide positive electrode material and vehicle |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117080448A (en) * | 2023-09-27 | 2023-11-17 | 荣耀终端有限公司 | Semi-solid lithium battery and terminal comprising same |
| CN117080448B (en) * | 2023-09-27 | 2024-03-19 | 荣耀终端有限公司 | Semi-solid lithium battery and terminal comprising same |
| CN118156480A (en) * | 2024-05-09 | 2024-06-07 | 浙江华宇钠电新能源科技有限公司 | Method for modifying surface of sodium ion battery oxide positive electrode material and vehicle |
| CN118156480B (en) * | 2024-05-09 | 2024-07-23 | 浙江华宇钠电新能源科技有限公司 | Method for modifying surface of sodium ion battery oxide positive electrode material and vehicle |
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